SD boyfriend always here

[PennyApril54]

I'm having a problem with my SD and her boyfriend. Both 20.
SD lives with us full-time, always has. I've been with DP for around 5 years and we have a 3 year old boy together. We've known each other a longer time, ten years or so.
DP split up with SD mum when she was very young. Mental health issues. Passed away due to this.
The problem I have is SD's boyfriend is always here at our home. Even when she is at work he is here in her room sleeping/ playing video games on his days off. I'm working from home he's watching TV or on the shower or lying on the couch in our lounge in his dressing gown watching TV. Or coming back from shops and cooking in the kitchen, making a mess that isn't cleared up and I can't get in to make lunch etc or in the evening our dinner.
I'm tired of it.
SD is rude to me when I try to bring it up. Partner doesn't want to rock the boat (think he feels bad for her about her own mum).
SD doesn't pay rent.
I've tried so hard with her (and bf) and so has my extended family to get along, involve her in all things , be warm etc but I'm so tired of this. What should I do?

Have a serious conversation with your partner and explain you’re considering breaking up over it. Boyfriend can stay two nights a week when SD is in, or you’ll support them with their first three months of rent and they can move out together. You signed up for a family, not a house share.

Just say he needs to go out when she’s not there and tidy up any mess he’s made. It’s your house.
If you’re at home and she’s out and he’s in, just go and say to him ‘sorry you need to leave now as x isn’t here.’
Switch the tv off etc. Make it very clear he needs to go and loaf around somewhere else. You don’t need to allow it.
Your husband needs to do some parenting too. He’s not her mate. It doesn’t sound like she’s about to move out anytime soon anyway.

So the boyfriend has effectively moved into your home. Have I got that right?

Thank you for your replies. Sorry I have messed up it should read SD's dad passed away. I am a man in this situation.

It feels like that!

The problem I have is I don't want to upset my partner but I am so fed up with this arrangement

I'd have the "this isn't on and won't be continuing" conversation directly with the boyfriend.
You don't know if dsd has told him you're all fine with it or not.
Tell him he's not been invited to move in, therefore he will be moving out.
Dsd and your DP can react however they want, but it's time you reclaimed your home and workspace.

Odd.

In your last thread in January, you live separately from your male partner, and you've only been together two years.

But now you live together and have a 3 year old, and presumably your partner is SD's mum, and therefore female?

There are some situations that are grey, but this is very clear. You have zero obligation to shelter SD's BF. They can be together, and he can shop and cook at his own family's home. You have a right to voice your preferences and needs in your own home.

This is not adding up. You said several times in your first post it was mum who had mh issues and died, now it's dad??